ChibiOS/RT 2.2.0发布，实时操作系统

ChibiOS/RT 2.2.0 发布，ChibiOS/RT 是一款小型的实时操作系统。

新版本包括支持多编译器(Cosmic, GCC, IAR, Keil, Raisonance)，驱动和演示。内部优化和文档的提升。

*** 2.2.0 ***
- NEW: The Cortex-Mx port now also supports the IAR and Keil compilers.
- NEW: Improvements to the Cortex-Mx port.
- NEW: Improved ARM port supporting both ARM7 and ARM9.
- NEW: Support for binary semaphores in the kernel.
- NEW: Improved kernel hooks.
- NEW: Extensive improvements to the STM32 platform support.
- NEW: SPI drivers for the AT91SAM7x, LPC11xx, LPC13xx, LPC214x, STM8S,
  platforms.
- NEW: Unified STM8 port for both the Cosmic and the Raisonance compilers.
- NEW: Demos for the STM8S-Discovery, STM8L-Discovery, STM32VL-Discovery
  boards.
- NEW: Improved almost all the existing device driver models in the HAL.
- NEW: Added test/example applications for all the device drivers in the HAL.
- NEW: Added support for the STM8L platform.
- NEW: New UART unbuffered serial device driver model.
- NEW: Greatly improved documentation.
- NEW: Lots of other minor improvements and optimizations, see the change
  log of the 2.1.x development branch for details.